Initial file dump from open source releaseHEADmaster

1 files changed, 685 insertions, 0 deletions

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
new file mode 100644
index 00000000..70a26c65
--- /dev/null
+++ b/fs/nfs/read.c
@@ -0,0 +1,685 @@
+/*
+ * linux/fs/nfs/read.c
+ *
+ * Block I/O for NFS
+ *
+ * Partial copy of Linus' read cache modifications to fs/nfs/file.c
+ * modified for async RPC by okir@monad.swb.de
+ */
+
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_page.h>
+#include <linux/module.h>
+
+#include "nfs4_fs.h"
+#include "internal.h"
+#include "iostat.h"
+#include "fscache.h"
+
+#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
+
+static const struct nfs_pageio_ops nfs_pageio_read_ops;
+static const struct rpc_call_ops nfs_read_common_ops;
+static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
+
+static struct kmem_cache *nfs_rdata_cachep;
+
+struct nfs_read_header *nfs_readhdr_alloc(void)
+{
+	struct nfs_read_header *rhdr;
+
+	rhdr = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
+	if (rhdr) {
+		struct nfs_pgio_header *hdr = &rhdr->header;
+
+		INIT_LIST_HEAD(&hdr->pages);
+		INIT_LIST_HEAD(&hdr->rpc_list);
+		spin_lock_init(&hdr->lock);
+		atomic_set(&hdr->refcnt, 0);
+	}
+	return rhdr;
+}
+EXPORT_SYMBOL_GPL(nfs_readhdr_alloc);
+
+static struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,
+						unsigned int pagecount)
+{
+	struct nfs_read_data *data, *prealloc;
+
+	prealloc = &container_of(hdr, struct nfs_read_header, header)->rpc_data;
+	if (prealloc->header == NULL)
+		data = prealloc;
+	else
+		data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		goto out;
+
+	if (nfs_pgarray_set(&data->pages, pagecount)) {
+		data->header = hdr;
+		atomic_inc(&hdr->refcnt);
+	} else {
+		if (data != prealloc)
+			kfree(data);
+		data = NULL;
+	}
+out:
+	return data;
+}
+
+void nfs_readhdr_free(struct nfs_pgio_header *hdr)
+{
+	struct nfs_read_header *rhdr = container_of(hdr, struct nfs_read_header, header);
+
+	kmem_cache_free(nfs_rdata_cachep, rhdr);
+}
+EXPORT_SYMBOL_GPL(nfs_readhdr_free);
+
+void nfs_readdata_release(struct nfs_read_data *rdata)
+{
+	struct nfs_pgio_header *hdr = rdata->header;
+	struct nfs_read_header *read_header = container_of(hdr, struct nfs_read_header, header);
+
+	put_nfs_open_context(rdata->args.context);
+	if (rdata->pages.pagevec != rdata->pages.page_array)
+		kfree(rdata->pages.pagevec);
+	if (rdata == &read_header->rpc_data) {
+		rdata->header = NULL;
+		rdata = NULL;
+	}
+	if (atomic_dec_and_test(&hdr->refcnt))
+		hdr->completion_ops->completion(hdr);
+	/* Note: we only free the rpc_task after callbacks are done.
+	 * See the comment in rpc_free_task() for why
+	 */
+	kfree(rdata);
+}
+EXPORT_SYMBOL_GPL(nfs_readdata_release);
+
+static
+int nfs_return_empty_page(struct page *page)
+{
+	zero_user(page, 0, PAGE_CACHE_SIZE);
+	SetPageUptodate(page);
+	unlock_page(page);
+	return 0;
+}
+
+void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
+			      struct inode *inode,
+			      const struct nfs_pgio_completion_ops *compl_ops)
+{
+	nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, compl_ops,
+			NFS_SERVER(inode)->rsize, 0);
+}
+EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
+
+void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
+{
+	pgio->pg_ops = &nfs_pageio_read_ops;
+	pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
+}
+EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
+
+int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
+		       struct page *page)
+{
+	struct nfs_page	*new;
+	unsigned int len;
+	struct nfs_pageio_descriptor pgio;
+
+	len = nfs_page_length(page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+	new = nfs_create_request(ctx, inode, page, 0, len);
+	if (IS_ERR(new)) {
+		unlock_page(page);
+		return PTR_ERR(new);
+	}
+	if (len < PAGE_CACHE_SIZE)
+		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+
+	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
+	nfs_pageio_add_request(&pgio, new);
+	nfs_pageio_complete(&pgio);
+	NFS_I(inode)->read_io += pgio.pg_bytes_written;
+	return 0;
+}
+
+static void nfs_readpage_release(struct nfs_page *req)
+{
+	struct inode *d_inode = req->wb_context->dentry->d_inode;
+
+	if (PageUptodate(req->wb_page))
+		nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
+
+	unlock_page(req->wb_page);
+
+	dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
+			req->wb_context->dentry->d_inode->i_sb->s_id,
+			(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
+			req->wb_bytes,
+			(long long)req_offset(req));
+	nfs_release_request(req);
+}
+
+/* Note io was page aligned */
+static void nfs_read_completion(struct nfs_pgio_header *hdr)
+{
+	unsigned long bytes = 0;
+
+	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
+		goto out;
+	while (!list_empty(&hdr->pages)) {
+		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+		struct page *page = req->wb_page;
+
+		if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
+			if (bytes > hdr->good_bytes)
+				zero_user(page, 0, PAGE_SIZE);
+			else if (hdr->good_bytes - bytes < PAGE_SIZE)
+				zero_user_segment(page,
+					hdr->good_bytes & ~PAGE_MASK,
+					PAGE_SIZE);
+		}
+		bytes += req->wb_bytes;
+		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
+			if (bytes <= hdr->good_bytes)
+				SetPageUptodate(page);
+		} else
+			SetPageUptodate(page);
+		nfs_list_remove_request(req);
+		nfs_readpage_release(req);
+	}
+out:
+	hdr->release(hdr);
+}
+
+int nfs_initiate_read(struct rpc_clnt *clnt,
+		      struct nfs_read_data *data,
+		      const struct rpc_call_ops *call_ops, int flags)
+{
+	struct inode *inode = data->header->inode;
+	int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
+	struct rpc_task *task;
+	struct rpc_message msg = {
+		.rpc_argp = &data->args,
+		.rpc_resp = &data->res,
+		.rpc_cred = data->header->cred,
+	};
+	struct rpc_task_setup task_setup_data = {
+		.task = &data->task,
+		.rpc_client = clnt,
+		.rpc_message = &msg,
+		.callback_ops = call_ops,
+		.callback_data = data,
+		.workqueue = nfsiod_workqueue,
+		.flags = RPC_TASK_ASYNC | swap_flags | flags,
+	};
+
+	/* Set up the initial task struct. */
+	NFS_PROTO(inode)->read_setup(data, &msg);
+
+	dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
+			"offset %llu)\n",
+			data->task.tk_pid,
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			data->args.count,
+			(unsigned long long)data->args.offset);
+
+	task = rpc_run_task(&task_setup_data);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+	rpc_put_task(task);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_initiate_read);
+
+/*
+ * Set up the NFS read request struct
+ */
+static void nfs_read_rpcsetup(struct nfs_read_data *data,
+		unsigned int count, unsigned int offset)
+{
+	struct nfs_page *req = data->header->req;
+
+	data->args.fh     = NFS_FH(data->header->inode);
+	data->args.offset = req_offset(req) + offset;
+	data->args.pgbase = req->wb_pgbase + offset;
+	data->args.pages  = data->pages.pagevec;
+	data->args.count  = count;
+	data->args.context = get_nfs_open_context(req->wb_context);
+	data->args.lock_context = req->wb_lock_context;
+
+	data->res.fattr   = &data->fattr;
+	data->res.count   = count;
+	data->res.eof     = 0;
+	nfs_fattr_init(&data->fattr);
+}
+
+static int nfs_do_read(struct nfs_read_data *data,
+		const struct rpc_call_ops *call_ops)
+{
+	struct inode *inode = data->header->inode;
+
+	return nfs_initiate_read(NFS_CLIENT(inode), data, call_ops, 0);
+}
+
+static int
+nfs_do_multiple_reads(struct list_head *head,
+		const struct rpc_call_ops *call_ops)
+{
+	struct nfs_read_data *data;
+	int ret = 0;
+
+	while (!list_empty(head)) {
+		int ret2;
+
+		data = list_first_entry(head, struct nfs_read_data, list);
+		list_del_init(&data->list);
+
+		ret2 = nfs_do_read(data, call_ops);
+		if (ret == 0)
+			ret = ret2;
+	}
+	return ret;
+}
+
+static void
+nfs_async_read_error(struct list_head *head)
+{
+	struct nfs_page	*req;
+
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);
+		nfs_list_remove_request(req);
+		nfs_readpage_release(req);
+	}
+}
+
+static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
+	.error_cleanup = nfs_async_read_error,
+	.completion = nfs_read_completion,
+};
+
+static void nfs_pagein_error(struct nfs_pageio_descriptor *desc,
+		struct nfs_pgio_header *hdr)
+{
+	set_bit(NFS_IOHDR_REDO, &hdr->flags);
+	while (!list_empty(&hdr->rpc_list)) {
+		struct nfs_read_data *data = list_first_entry(&hdr->rpc_list,
+				struct nfs_read_data, list);
+		list_del(&data->list);
+		nfs_readdata_release(data);
+	}
+	desc->pg_completion_ops->error_cleanup(&desc->pg_list);
+}
+
+/*
+ * Generate multiple requests to fill a single page.
+ *
+ * We optimize to reduce the number of read operations on the wire.  If we
+ * detect that we're reading a page, or an area of a page, that is past the
+ * end of file, we do not generate NFS read operations but just clear the
+ * parts of the page that would have come back zero from the server anyway.
+ *
+ * We rely on the cached value of i_size to make this determination; another
+ * client can fill pages on the server past our cached end-of-file, but we
+ * won't see the new data until our attribute cache is updated.  This is more
+ * or less conventional NFS client behavior.
+ */
+static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc,
+			    struct nfs_pgio_header *hdr)
+{
+	struct nfs_page *req = hdr->req;
+	struct page *page = req->wb_page;
+	struct nfs_read_data *data;
+	size_t rsize = desc->pg_bsize, nbytes;
+	unsigned int offset;
+
+	offset = 0;
+	nbytes = desc->pg_count;
+	do {
+		size_t len = min(nbytes,rsize);
+
+		data = nfs_readdata_alloc(hdr, 1);
+		if (!data) {
+			nfs_pagein_error(desc, hdr);
+			return -ENOMEM;
+		}
+		data->pages.pagevec[0] = page;
+		nfs_read_rpcsetup(data, len, offset);
+		list_add(&data->list, &hdr->rpc_list);
+		nbytes -= len;
+		offset += len;
+	} while (nbytes != 0);
+
+	nfs_list_remove_request(req);
+	nfs_list_add_request(req, &hdr->pages);
+	desc->pg_rpc_callops = &nfs_read_common_ops;
+	return 0;
+}
+
+static int nfs_pagein_one(struct nfs_pageio_descriptor *desc,
+			  struct nfs_pgio_header *hdr)
+{
+	struct nfs_page		*req;
+	struct page		**pages;
+	struct nfs_read_data    *data;
+	struct list_head *head = &desc->pg_list;
+
+	data = nfs_readdata_alloc(hdr, nfs_page_array_len(desc->pg_base,
+							  desc->pg_count));
+	if (!data) {
+		nfs_pagein_error(desc, hdr);
+		return -ENOMEM;
+	}
+
+	pages = data->pages.pagevec;
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);
+		nfs_list_remove_request(req);
+		nfs_list_add_request(req, &hdr->pages);
+		*pages++ = req->wb_page;
+	}
+
+	nfs_read_rpcsetup(data, desc->pg_count, 0);
+	list_add(&data->list, &hdr->rpc_list);
+	desc->pg_rpc_callops = &nfs_read_common_ops;
+	return 0;
+}
+
+int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
+		       struct nfs_pgio_header *hdr)
+{
+	if (desc->pg_bsize < PAGE_CACHE_SIZE)
+		return nfs_pagein_multi(desc, hdr);
+	return nfs_pagein_one(desc, hdr);
+}
+EXPORT_SYMBOL_GPL(nfs_generic_pagein);
+
+static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
+{
+	struct nfs_read_header *rhdr;
+	struct nfs_pgio_header *hdr;
+	int ret;
+
+	rhdr = nfs_readhdr_alloc();
+	if (!rhdr) {
+		desc->pg_completion_ops->error_cleanup(&desc->pg_list);
+		return -ENOMEM;
+	}
+	hdr = &rhdr->header;
+	nfs_pgheader_init(desc, hdr, nfs_readhdr_free);
+	atomic_inc(&hdr->refcnt);
+	ret = nfs_generic_pagein(desc, hdr);
+	if (ret == 0)
+		ret = nfs_do_multiple_reads(&hdr->rpc_list,
+					    desc->pg_rpc_callops);
+	if (atomic_dec_and_test(&hdr->refcnt))
+		hdr->completion_ops->completion(hdr);
+	return ret;
+}
+
+static const struct nfs_pageio_ops nfs_pageio_read_ops = {
+	.pg_test = nfs_generic_pg_test,
+	.pg_doio = nfs_generic_pg_readpages,
+};
+
+/*
+ * This is the callback from RPC telling us whether a reply was
+ * received or some error occurred (timeout or socket shutdown).
+ */
+int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
+{
+	struct inode *inode = data->header->inode;
+	int status;
+
+	dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
+			task->tk_status);
+
+	status = NFS_PROTO(inode)->read_done(task, data);
+	if (status != 0)
+		return status;
+
+	nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, data->res.count);
+
+	if (task->tk_status == -ESTALE) {
+		set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
+		nfs_mark_for_revalidate(inode);
+	}
+	return 0;
+}
+
+static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
+{
+	struct nfs_readargs *argp = &data->args;
+	struct nfs_readres *resp = &data->res;
+
+	/* This is a short read! */
+	nfs_inc_stats(data->header->inode, NFSIOS_SHORTREAD);
+	/* Has the server at least made some progress? */
+	if (resp->count == 0) {
+		nfs_set_pgio_error(data->header, -EIO, argp->offset);
+		return;
+	}
+	/* Yes, so retry the read at the end of the data */
+	data->mds_offset += resp->count;
+	argp->offset += resp->count;
+	argp->pgbase += resp->count;
+	argp->count -= resp->count;
+	rpc_restart_call_prepare(task);
+}
+
+static void nfs_readpage_result_common(struct rpc_task *task, void *calldata)
+{
+	struct nfs_read_data *data = calldata;
+	struct nfs_pgio_header *hdr = data->header;
+
+	/* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
+	if (nfs_readpage_result(task, data) != 0)
+		return;
+	if (task->tk_status < 0)
+		nfs_set_pgio_error(hdr, task->tk_status, data->args.offset);
+	else if (data->res.eof) {
+		loff_t bound;
+
+		bound = data->args.offset + data->res.count;
+		spin_lock(&hdr->lock);
+		if (bound < hdr->io_start + hdr->good_bytes) {
+			set_bit(NFS_IOHDR_EOF, &hdr->flags);
+			clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
+			hdr->good_bytes = bound - hdr->io_start;
+		}
+		spin_unlock(&hdr->lock);
+	} else if (data->res.count != data->args.count)
+		nfs_readpage_retry(task, data);
+}
+
+static void nfs_readpage_release_common(void *calldata)
+{
+	nfs_readdata_release(calldata);
+}
+
+void nfs_read_prepare(struct rpc_task *task, void *calldata)
+{
+	struct nfs_read_data *data = calldata;
+	NFS_PROTO(data->header->inode)->read_rpc_prepare(task, data);
+	if (unlikely(test_bit(NFS_CONTEXT_BAD, &data->args.context->flags)))
+		rpc_exit(task, -EIO);
+}
+
+static const struct rpc_call_ops nfs_read_common_ops = {
+	.rpc_call_prepare = nfs_read_prepare,
+	.rpc_call_done = nfs_readpage_result_common,
+	.rpc_release = nfs_readpage_release_common,
+};
+
+/*
+ * Read a page over NFS.
+ * We read the page synchronously in the following case:
+ *  -	The error flag is set for this page. This happens only when a
+ *	previous async read operation failed.
+ */
+int nfs_readpage(struct file *file, struct page *page)
+{
+	struct nfs_open_context *ctx;
+	struct inode *inode = page_file_mapping(page)->host;
+	int		error;
+
+	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
+		page, PAGE_CACHE_SIZE, page_file_index(page));
+	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
+	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
+
+	/*
+	 * Try to flush any pending writes to the file..
+	 *
+	 * NOTE! Because we own the page lock, there cannot
+	 * be any new pending writes generated at this point
+	 * for this page (other pages can be written to).
+	 */
+	error = nfs_wb_page(inode, page);
+	if (error)
+		goto out_unlock;
+	if (PageUptodate(page))
+		goto out_unlock;
+
+	error = -ESTALE;
+	if (NFS_STALE(inode))
+		goto out_unlock;
+
+	if (file == NULL) {
+		error = -EBADF;
+		ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
+		if (ctx == NULL)
+			goto out_unlock;
+	} else
+		ctx = get_nfs_open_context(nfs_file_open_context(file));
+
+	if (!IS_SYNC(inode)) {
+		error = nfs_readpage_from_fscache(ctx, inode, page);
+		if (error == 0)
+			goto out;
+	}
+
+	error = nfs_readpage_async(ctx, inode, page);
+
+out:
+	put_nfs_open_context(ctx);
+	return error;
+out_unlock:
+	unlock_page(page);
+	return error;
+}
+
+struct nfs_readdesc {
+	struct nfs_pageio_descriptor *pgio;
+	struct nfs_open_context *ctx;
+};
+
+static int
+readpage_async_filler(void *data, struct page *page)
+{
+	struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
+	struct inode *inode = page_file_mapping(page)->host;
+	struct nfs_page *new;
+	unsigned int len;
+	int error;
+
+	len = nfs_page_length(page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+
+	new = nfs_create_request(desc->ctx, inode, page, 0, len);
+	if (IS_ERR(new))
+		goto out_error;
+
+	if (len < PAGE_CACHE_SIZE)
+		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+	if (!nfs_pageio_add_request(desc->pgio, new)) {
+		error = desc->pgio->pg_error;
+		goto out_unlock;
+	}
+	return 0;
+out_error:
+	error = PTR_ERR(new);
+out_unlock:
+	unlock_page(page);
+	return error;
+}
+
+int nfs_readpages(struct file *filp, struct address_space *mapping,
+		struct list_head *pages, unsigned nr_pages)
+{
+	struct nfs_pageio_descriptor pgio;
+	struct nfs_readdesc desc = {
+		.pgio = &pgio,
+	};
+	struct inode *inode = mapping->host;
+	unsigned long npages;
+	int ret = -ESTALE;
+
+	dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			nr_pages);
+	nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
+
+	if (NFS_STALE(inode))
+		goto out;
+
+	if (filp == NULL) {
+		desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
+		if (desc.ctx == NULL)
+			return -EBADF;
+	} else
+		desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
+
+	/* attempt to read as many of the pages as possible from the cache
+	 * - this returns -ENOBUFS immediately if the cookie is negative
+	 */
+	ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
+					 pages, &nr_pages);
+	if (ret == 0)
+		goto read_complete; /* all pages were read */
+
+	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
+
+	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
+
+	nfs_pageio_complete(&pgio);
+	NFS_I(inode)->read_io += pgio.pg_bytes_written;
+	npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	nfs_add_stats(inode, NFSIOS_READPAGES, npages);
+read_complete:
+	put_nfs_open_context(desc.ctx);
+out:
+	return ret;
+}
+
+int __init nfs_init_readpagecache(void)
+{
+	nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
+					     sizeof(struct nfs_read_header),
+					     0, SLAB_HWCACHE_ALIGN,
+					     NULL);
+	if (nfs_rdata_cachep == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void nfs_destroy_readpagecache(void)
+{
+	kmem_cache_destroy(nfs_rdata_cachep);
+}